Immunological cross‐reactivity between the light‐harvesting chlorophylla/b‐proteins of a marine green alga and spinach

Immunoblotting was used to probe the reactivity of rabbit polyclonal antibodies against PS1I and PSI light‐harvesting chlorophyll a/b‐proteins of spinach ( Spinacea oleracea L.) with the light‐harvesting complexes of a siphonaceous marine alga, Codium , that have more chlorophyll b, siphonaxanthin and siphonein instead of the lutein. The spinach LHCII antibodies cross‐reacted only with the apoproteins of Cod‐ium LHCII. Antisera against the spinach LHCI apoproteins showed strong affinity for the apoproteins of Codium LHCI, and also reacted with the polypeptides of spinach LHCII and Codium LHCII. Our results indicate some similarities in the amino acid sequences between the Codium siphonaxanthin‐Chl a/fe‐proteins of LHCII and LHCI and the corresponding spinach lutein‐chlorophyll a/b‐proteins.